Inhibitors of platelet-derived growth factor

ABSTRACT

A method of inhibiting the binding of PDGF using compounds of the formula I ##STR1## useful in the treatment of atherosclerosis, cancer, retinal detachment, pulmonary fibrosis, arthritis, psoriasis and glomerulonephritis, and restenosis following angioplasty or vascular surgery is disclosed. 
     Also disclosed are pharmaceutical compositions and novel PDGF inhibitory compounds of the formula ##STR2## or a pharmaceutically acceptable addition salt thereof, useful in the treatment of atherosclerosis, cancer, retinal detachment, pulmonary fibrosis, arthritis, psoriasis and glomerulonephritis, and restenosis following angioplasty or vascular surgery.

BACKGROUND OF THE INVENTION

The present invention relates to a method of inhibiting the binding of platelet-derived growth factor (PDGF) using N-alkyl- and N-aryl-sulfonyl phthalimides, maleimides and heterodicarboxamides.

The invention also relates to certain N-alkyl- and N-arylsulfonyl phthalimides, maleimides and heterodicarboxamides useful as inhibitors of PDGF.

Furthermore, the invention relates to a pharmaceutical composition comprising an N-alkyl- or N-aryl-sulfonyl phthalimide, maleimide or heterodicarboxamide useful as an inhibitor of PDGF.

The platelet-derived growth factors (PDGF) are a family of polypeptide mitogens, produced by a variety of different cell types, which stimulate the proliferation of most mesenchymal cells and possibly certain epithelial and endothelial cells. PDGF binds to specific cell surface receptors which possess intrinsic tyrosine kinase activity. Binding of PDGF activates the kinase activity, thereby initiating a cascade of biochemical events culminating in cell division. PDGF cell division can occur by a paracrine mechanism, in which PDGF produced by one cell stimulates the division of other cells, or by an autocrine mechanism, in which a cell stimulates its own division by endogenous production of PDGF.

A compound which inhibits the binding PDGF to its receptor blocks the biological activity of the growth factor. This biological activity includes vascular cell proliferation in atherosclerosis or restenosis following angioplasty or vascular surgery, and division of certain tumor cells, fibroblasts, mesangial cells and epidermal cells. PDGF is also a potent chemotactic agent, stimulating infiltration of macrophages into arterial tissue in atherosclerosis and into the glomerulus in glomerulonephritis. PDGF is also involved in the elaboration of extracellular matrix proteins by retinal pigment epithelial cells, indirectly leading to retinal detachment and blindness. Therefore, a PDGF inhibitor should be useful in the treatment of a variety of diseases, including atherosclerosis, cancer, retinal detachment, pulmonary fibrosis, arthritis, psoriasis and glomerulonephritis, and for blocking the smooth muscle cell hyperplasia which occurs in transplant atherosclerosis and following angioplasty or vascular surgery.

SUMMARY OF THE INVENTION

The method of inhibiting the binding of platelet-derived growth factor (PDGF) of the present invention comprises treating a mammal in need of such treatment with a inhibitory effective does of a compound of the formula I ##STR3## or a pharmaceutically acceptable addition salt thereof, wherein p is 0,1, 2,3,4,5, or 6 and R is hydrogen or an aryl group substituted by 1-5 substitutents R⁴, provided that R is not hydrogen when p=0;

R¹ and R² are independently selected from the group consisting of hydrogen, C₁ -C₈ alkyl, aryl, cyano and --NHS(O)₂ alkyl; or

R¹ and R² taken together comprise a fused ring of the formula ##STR4##

n is 0, 1, 2 or 3;

q is 0, 1, 2, 3 or 4;

Z¹, Z², Z³ or Z⁴ are independently nitrogen or carbon, provided that at least one of Z¹, Z², Z³ or Z⁴ is nitrogen;

X, R³ and R⁵ are independently selected from the group consisting of hydrogen, halogeno, hydroxy, C₁ -C₈ alkyl, C₁ -C₈ alkenyl, C₁ -C₈ alkynyl, C₁ -C₈ alkoxy, aryloxy, amino, alkylamino, dialkylamino, arylamino, diarylamino, trialkylammonium, thio, --S(O)₂ R⁶, --S(O)_(m) R⁷, --SO₃, nitro, --NHS(O)₂ alkyl, carboxyl, alkoxycarbonyl, carboxamido, N-alkylcarboxamido, N,N-dialkylcarboxamido, alkylcarbonylamino, arylcarbonylamino, alkylaminocarbonyloxy, alkoxycarbonyloxy, alkylcarbonyloxy, trifluoromethyl, cyano, aryl, heteroaryl, and substituted aryl and substituted heteroaryl, wherein the substituents are 1-5 groups R⁴ ; and

wherein the R⁴ substituents are independently selected from the group consisting of hydrogen, halogeno, C₁ -C₈ alkenyl, C₁ -C₈ alkynyl, hydroxy, C₁ -C₈ alkyl, Y-substituted alkyl, C₁ -C₈ alkoxy, aryloxy, amino, alkylamino, dialkylamino, arylamino, diarylamino, trialkylammonium, thio, --SO₂ R⁶, --S(O)_(m) R⁷, --SO₃, nitro, carboxyl, alkoxycarbonyl, benzyloxycarbonyl, alkenyloxycarbonyl, carboxamido, N-phthalimido, cyanoalkoxycarbonyl, carboxyalkoxycarbonyl, benzyloxycarbonylalkoxycarbonyl, N-alkyl-carboxamido, N,N-dialkylcarboxamido, trifluoromethyl, cyano, aryl and heteroaryl; and

Y is selected from the group consisting of halogeno, trialkylammonium, amino, carboxy, pyridinium, triarylphosphonium, benzyloxycarbonyl, hexamethylenetetraminium, --N═CH--alkyl, --N═CH--aryl and --N═CH--N(alkyl)₂,;

R⁶ is amino, arylamino, alkylamino or dialkylamino;

R⁷ is C₁ -C₈ alkyl or aryl; and

m is 0, 1 or 2.

This invention also relates to novel PDGF inhibitory compounds of the formula Ia ##STR5## or a pharmaceutically acceptable addition salt thereof, wherein R^(a) is an aryl group substituted by 1-5 substitutents R^(4a) ;

R^(1a) and R^(2a) are independently selected from the group consisting of aryl, cyano and --NHS(O)₂ alkyl; or R^(1a) and R^(2a) together comprise a fused ring of the formula ##STR6##

n is 0, 1, 2 or 3;

q is 0, 1, 2, 3 or 4;

Z¹, Z², Z³ or Z⁴ are independently nitrogen or carbon, provided that at least one of Z¹, Z², Z³ or Z⁴ is nitrogen;

R^(3a) and R^(5a) are independently selected from the group consisting of hydroxy, C₁ -C₈ alkyl, C₁ -C₈ alkenyl, C₁ -C₈ alkynyl, C₁ -C₈ alkoxy, aryloxy, arylamino, diarylamino, trialkylammonium, thio, --S(O)₂ R⁶, --S(O)_(m) R⁷, --SO₃, nitro, --NHS(O)₂ alkyl, carboxyl, alkoxycarbonyl, carboxamido, N-alkylcarboxamido, N,N-dialkylcarboxamido, arylcarbonylamino, alkylaminocarbonyloxy, alkoxycarbonyloxy, alkylcarbonyloxy, trifluoromethyl, cyano, aryl, heteroaryl, and substituted aryl and substituted heteroaryl, wherein the substituents are 1-5 groups R^(4a) ; and

wherein the R^(4a) substituents are independently selected from the group consisting of C₁ -C₈ alkenyl, C₁ -C₈ alkynyl, hydroxy, Y-substituted alkyl, alkylamino, dialkylamino, arylamino, diarylamino, trialkylammonium, thio, --S(O)_(m) R⁷, --SO₃, carboxyl, alkoxycarbonyl, benzyloxycarbonyl, alkenyloxycarbonyl, carboxamido, N-phthalimido, cyanoalkoxycarbonyl, carboxyalkoxycarbonyl, benzyloxycarbonylalkoxycarbonyl, N,N-dialkylcarboxamido, trifluoromethyl, cyano and heteroaryl; and

Y is selected from the group consisting of halogeno, trialkylammorium, amino, carboxy, pyridinium, triarylphosphonium, benzyloxycarbonyl, hexamethylenetetraminium, --N═CH--alkyl, --N═CH--aryl and --N═CH--N(alkyl)₂ ;

R⁷ is C₁ -C₈ alkyl or aryl; and

m is 0, 1 or 2.

The following groups of compounds of the formula I are preferred for use in the method of this invention.

Compounds of the formula I wherein p=0 and R is phenyl or naphthyl, substituted by 1-5 substituents R⁴.

Compounds of the formula I wherein p=1-6, X is hydrogen and R is phenyl or naphthyl, substituted by 1-5 substituents R⁴.

Compounds of the formula I wherein R¹ and R² together comprise a fused ring of the formula ##STR7## and wherein R³ is selected from the group consisting of hydrogen, halogeno, nitro and amino.

Compounds of the formula I wherein R¹ and R² together comprise a fused ring of the formula ##STR8## wherein Z¹ and Z⁴ are each nitrogen and n=0.

The following groups of compounds of formula I are more preferred for use in the method of this invention:

compounds of the formula ##STR9## wherein: R³ is selected from the group consisting of hydrogen, halogeno, nitro and amino; and R is phenyl or naphthyl, substituted by 1-5 substituents R⁴ ; and

compounds of the formula ##STR10## wherein: X is hydrogen; p=1-6; R³ is selected from the group consisting of hydrogen, halogeno, nitro and amino; and R is phenyl or naphthyl, substituted by 1-5 substituents R⁴.

The following groups of compounds of formula I are especially preferred for use in the method of this invention:

compounds of the formula ##STR11## wherein: X is hydrogen; p=1-6; R is phenyl or naphthyl, substituted by 1-5 substituents R⁴ ; and R⁴ is selected from the group consisting of hydrogen, halogeno, nitro, Y-substituted alkyl, amino, alkylamino, dialkylamino, and alkoxycarbonyl; and

compounds of the formula ##STR12##

wherein: R is phenyl or naphthyl, substituted by 1-5 substituents R⁴ R⁴ is selected from the group consisting of hydrogen, halogeno, nitro, Y-substituted alkyl, amino, alkylamino, dialkylamino, alkoxycarbonyl, benzyloxycarbonyl, and alkoxyalkoxycarbonyl; and Y is halogeno, benzyloxycarbonyl or triphenylphosphonium.

Preferred compounds of formula Ia are those wherein R^(1a) and R^(2a) together comprise a fused ring of the formula ##STR13##

Also preferred are compounds of formula Ia wherein R^(1a) and R^(2a) together comprise a fused ring of the formula ##STR14##

Another group of preferred compounds of the formula Ia is that wherein R^(a) is phenyl or naphthyl, substituted by 1-5 group R^(4a).

More preferred are compounds of the formula Ia wherein R^(1a) and R^(2a) together comprise a fused ring of the formula ##STR15##

Another group of more preferred compounds of the formula Ia is that wherein R^(a) is phenyl or naphthyl, substituted by 1-5 groups R^(4a) and R^(4a) is selected from the group consisting of Y-substituted alkyl, alkylamino, dialkylamino or alkoxycarbonyl.

Especially preferred are compounds of the formula Ia wherein R^(a) is phenyl or naphthyl, substituted by 1-5 groups R^(4a), R^(4a) is selected from the group consisting of Y-substituted alkyl, alkylamino, dialkylamino or alkoxycarbonyl, and Y is halogeno, benzyloxycarbonyl or triphenylphosphonium.

This invention also relates to pharmaceutical compositions comprising a PDGF inhibitor of formula Ia in a pharmaceutically acceptable carrier.

DETAILED DESCRIPTION

As used herein, the term "alkyl" means straight or branched alkyl chains of 1 to 8 carbon atoms, and "alkoxy" similarly refers to alkoxy groups having 1 to 8 carbon atoms.

"Halogeno" means fluorine, chlorine, bromine or iodine radicals.

"Aryl" means mono-cyclic or fused ring bicyclic carbocyclic aromatic groups having 6 to 10 ring members and "heteroaryl" means mono-cyclic or fused ring bicyclic aromatic groups having 5-10 ring members wherein 1-3 ring members are independently nitrogen, oxygen or sulfur. In substituted aryl and heteraryl groups the carbon ring members are substituted by one to five substituents R⁴. Examples of aryl groups are: phenyl and napthyl. Examples of heteroaryl groups are: pyridyl, pyrimidinyl, pyrazinyl, pyrrolyl, triazinyl, imidazolyl, furanyl, and thienyl.

Compounds of the formula Ia are a subgenus of compounds of the formula I, therefore all compounds of formula Ia are also compounds of formula I.

Certain compounds of the invention e.g., those with a basic amino group, also form pharmaceutically acceptable salts with organic and inorganic acids. Examples of suitable acids for such salt formation are hydrochloric, sulfuric, phosphoric, acetic, citric, oxalic, malonic, salicylic, malic, fumaric, succinic, ascorbic, maleic, methanesulfonic and other mineral and carboxylic acids well known to those skilled in the art. The salts are prepared by contacting the free base form with a sufficient amount of the desired acid to produce a salt in the conventional manner. The free base forms may be regenerated by treating the salt with a suitable dilute aqueous base solution such as dilute aqueous sodium hydroxide, potassium carbonate, ammonia and sodium bicarbonate. The free base forms differ from the respective salt forms somewhat in certain physical properties, such as solubility in polar solvents, but the salts are otherwise equivalent to their respective free base forms for purposes of this invention.

Certain compounds of the invention are acidic e.g., those compounds which possess a carboxyl group. These compounds form pharmaceutically acceptable salts with inorganic and organic bases. Examples of such salts are the sodium, potassium, calcium, aluminum, gold and silver salts. Also included are salts formed with pharmaceutically acceptable amines such as ammonia, alkyl amines, hydroxyalkylamines, N-methylglucamine and the like.

The salts may be formed by conventional means, as by reacting the free acid or base form of the product with one or more equivalents of the appropriate base or acid, respectively, in a solvent or medium in which the salt is insoluble, or in a solvent such as water which is then removed in vacuo or by freeze-drying or by exchanging the cations of an existing salt for another cation on a suitable ion exchange resin.

Compounds of the present invention can be prepared using methods well known to those skilled in the art. For example, compounds of the formula I can be prepared via the following methods.

In a method for preparing compounds of the formula I, wherein p is 1, 2, 3, 4, 5 or 6, a bromide of the formula V is converted to the grignard reagent by treatment with Mg, then reacted with SO₂. The resulting magenesium sulfinate salt is treated with sulfuryl chloride to form a sulfonyl chloride of the formula VI. Sulfonyl chloride VI is then reacted with a dicarboximide of the formula VII to form a compound of the formula I, wherein p is 1, 2, 3, 4, 5 or 6. ##STR16##

Starting bromides of formula V and dicarboximides of formula VII are commercially available or can be prepared by well known methods.

In a method for preparing compounds of the formula Ib, i.e., compounds of formula I wherein p=0 and R is an aryl group substituted by 1-5 substituents R⁴, an amine of the formula II, wherein R^(b) is an aryl group as defined above, is converted to the analogous sulfonamide III. Reaction of the sulfonamide III with a diacid chloride derivative of the formula IV gives the desired sulfonyldicarboximide Ib. ##STR17##

Starting amines of the formula II are commercially available or readily prepared by well known methods. Diacid chlorides of the formula IV are either commercially available or can be prepared from the corresponding diacids VIII by treatment with a suitable chlorinating agent, such as oxalkyl chloride or thionyl chloride. The diacids of the formula VIII are either commercially available or can be prepared by methods well known to those skilled in the art. ##STR18##

In a method for preparing compounds of the formula Ib, wherein one of the R⁴ substituents is bromomethyl, a corresponding compound of the formula Ib, wherein one of the R⁴ substituents is methyl, is treated with N-bromosuccinimide.

In a method for preparing compounds of the formula Ib, wherein and one of the R⁴ substituents is (trialkylammonium)methyl or (triphenylphosphonium)methyl, a corresponding compound of the formula Ib, wherein one of the R⁴ substituents is bromomethyl, is treated with a trialkylamine or triphenylphoshpine, respectively.

In the above process, one skilled in the art will appreciate that it is desirable and sometimes necessary to protect the groups in column 1 of Table 1. Conventional protecting groups are operable. Preferred protected groups appear in column 2 of Table 1.

                  TABLE 1                                                          ______________________________________                                         PROTECTED GROUPS                                                               1. GROUP TO                                                                    BE PROTECTED   2. PROTECTED GROUP                                              ______________________________________                                         COOH                                                                                           ##STR19##                                                       ##STR20##                                                                                     ##STR21##                                                       ##STR22##                                                                                     ##STR23##                                                      OH                                                                                             ##STR24##                                                      NHR, wherein R is any substituent on an amino group within the scope of        the claims                                                                                     ##STR25##                                                      NH.sub.2                                                                                       ##STR26##                                                      ______________________________________                                    

Of course other protecting groups well known in the art may be used. After the reaction of reactions, the protecting groups may be removed by standard procedures well known in the art.

We have found that the compounds of formula I are inhibitors of PDGF and thus block the biological activity of PDGF. Therefore, the compounds of this invention are useful in the treatment of the various diseases, described above, in which PDGF activity plays a role.

In addition to the compound aspect, the present invention therefore also relates to a method of treating the aforementioned diseases. The compound is preferably administered in a pharmaceutically acceptable carrier suitable for oral administration.

The in vitro activity of compounds of formula I can be determined by the following procedure.

PDGF Receptor Binding Assay

The ability of a compound of the present invention to prevent binding of PDGF to the PDGF receptor can be determined using the following method.

Seed 1.5×10⁴ human foreskin fibroblasts (HSF) in 24 well dishes in growth medium [Dulbecco's Modified Eagle's Medium (DMEM)+10% fetal bovine serum+2 mM glutamine+penicillin (50 U/mL)/streptomycin (50 μg/mL)] and grow to approximately 70% confluence. Remove the growth medium by aspiration and wash the HSF one or two times in 1 mL of phosphate-buffered saline. Replace the medium with 1 mL of DMEM+2% equine plasma-derived serum (PDGF deficient)+2 mM glutamine+penicillin (50 U/mL) streptomycin (50 μg/mL) and incubate for 48 hours.

The receptor binding assay is carried out at 4° C. using ice-cold solutions unless otherwise noted, and all samples should be in duplicate.

Incubate the cells for 4 hours in the presence of 0, 1, 2, 4, 16, 32 or 200 ng of recombinant human c-sis (PDGF B chain homodimer) and 0.2 ng of ¹²⁵ I labelled c-sis. Solubilize the cells, then count the samples in a gamma counter. The concentration of PDGF in an unknown is determined by ascertaining the amount of unlabeled c-sis which must be added to the cells to give the number of counts in the unknown.

A working solution of the unlabeled c-sis used in the above procedure is prepared as follows. Prepare a stock solution of 1 mg/ml in 1M acetic acid, 0.15M NaCl. Add 1 μL (1 μg) of the stock solution to 99 μL of DMEM containing 2 mg/ml gelatin. Make a 1:10 dilution to obtain a working dilution of 1 ng/μL.

The present invention also relates to a pharmaceutical composition comprising a compound of formula I of this invention and a pharmaceutically acceptable carrier. The compounds of formula I can be administered in any conventional oral dosage form such as capsules, tablets powders, cachets, suspensions or solutions. The formulations and pharmaceutical compositions can be prepared using conventional pharmaceutically acceptable excipients and additives and conventional techniques. Such pharmaceutically acceptable excipients and additives include non-toxic compatible fillers, binders, disintegrnts, buffers, preservatives, anti-oxidants, lubricants, flavorings, thickeners, coloring agents, emulsifiers and the like.

The following are illustrative examples of preparing compounds of the formula I. ##STR27##

Prepare a solution of 2-methyl-5-chloroaniline (10 g) in 150 mL of concentrated HCl. Add 75 g of ice followed by a cold solution of sodium nitrite (21 g) in 30 mL of water. Stir the mixture at 0° C. for one hour, then add the mixture to a 30% solution of sulfur dioxide in glacial acetic acid. Immediately add a solution of cuprous chloride dihydrate (12 g) in 21 mL water. Stir the mixture at 0° C. for two hours. Filter the solids, then extract the filtrate with diethyl ether. Concentrate the ether extract, under vacuum, to a residue. Combine the residue and the filtered solids, then dissolve in concentrated aqueous ammonia and stir the solution overnight at ambient temperature. Filter the resulting mixture, then concentrate the filtrate until crystallization begins. Cool the filtrate, then collect the solids by filtration to give 16 grams of the title compound. ##STR28## Combine 1.28 g of magnesium turnings and 10 mL diethyl ether, then add 6.0 mL of phenethylbromide at a rate sufficient to maintain the solvent at gentle reflux. When addition of the bromide is complete, stir the mixture for 0.5 h, then cool to -10° C. Bubble sulfur dioxide into the mixture until the sulfinate salt precipitates. Remove the solvent under vacuum and suspend the solid residue in 20 mL methylene chloride. Cool the suspension to 0° C., then slowly add sulfuryl chloride (100 mole %). Allow the mixture to warm to 22° C. and stir for 0.5 h. Wash with 10 mL water, dry the organic solution over MgSO₄, then remove the solvent under vacuum to give 8.3 g of the title compound.

EXAMPLE 1 ##STR29## Dissolve the product of Preparation 1 (10 g) in 30 mL of toluene and add 10 g phthaloyl chloride. Heat the mixture at reflux overnight, allow the mixture to cool to room temperature, then filter to obtain 12 g of the title compound, m.p. 203°-205° C.

The following compounds were prepared by substantially the same procedure: ##STR30##

EXAMPLE 2 ##STR31##

Dissolve the product of Example 1 (15 g) and N-bromosuccinimide (19 g) in 400 mL tetrachloromethane, and heat the solution at reflux for 12 hours. Cool the solution then wash with NaHSO₃ (aqueous), then three times with water. Dry the organic solution over Na₂ SO₄, filter, then evaporate the solvent to a solid residue. Recrystallize the residue from CH₂ Cl₂ to give the title compound, m.p. 164° C.

The following compounds were prepared by substantially the same procedure from suitable starting materials, but adding a trace (0.05 g) of benzoyl perioxide to the reaction mixture when solubility of the starting material is low: ##STR32##

EXAMPLE 3 ##STR33##

Combine the product of Example 5(5.2g), 2.2 ml (120 mol%) triethyl amine and 15 ml methylene chloride and heat the mixture at reflux. After 2 h, filter to collect the precipitate and the cool the filtrate overnight at -10° C. Filter to collect the second crop of product. Dry the combined product fractions in vacuo to afford 5.65 g (86%) of the title compound.

Anal. Calcd. for C₂₁ H₂₅ N₂ O₄ SBr: C, 52.39;H,5.20;N,5.82;

Found: C,52.07;H,5.38;N,5.80.

The following compounds were prepared by substantially the same procedure: ##STR34##

EXAMPLE 4 ##STR35##

Combine the sulfonyl chloride of Preparation 2 (3.2 g), phthalimide (2.3 g) and 50 mL of methylene chloride. Add 10 mL of 40% tetrabutylammonium hydroxide (aqueous) and stir the biphasic mixture while heating to 60° C. After stirring at 60° C. for 3-5 h, cool the mixture and separate the organic phase. Wash the organic solution with 10 mL of 1N HCl (aqueous), then with 10 mL water. Dry the organic solution over MgSO₄ then concentrate to a residue. Purify the residue on silica gel (1:1 hexane/ethyl acetate) to give 1.47 g of the title compound, mp=165°-166° C.

The following compounds were prepared by substantially the same procedure: ##STR36##

Using the methods described above, the following in vitro data were obtained for the preferred compounds, which are identified in the following tables by the corresponding example numbers.

    ______________________________________                                         Example  Binding       Example  Binding                                        #        IC50          #        IC50                                           ______________________________________                                         1        3             1A       4                                                       14                     4.2                                            1B       1.8           1C       3                                                       10.3                   >10                                                     9.1                                                                   1D       3             1E       1                                                                              0.8                                                                            1.6                                            1F       2             1G       5                                                       2                      7.2                                            1H       3             1I       4.8                                                     0.5                    4.1                                            1J       24.5          1K       100                                                     75                                                                    1L       4.3           1M       3                                                       4.7                    6                                              1N       3             1O       10                                                      >10                    >100                                           1P       <1            1Q       4.4                                                     0.1                    4.9                                            1R       0.5           1S       0.75                                                    0.1                    0.2                                                                            4(4)                                           1T       1.0           1U       5.5                                                     0.04                                                                  1V       13            1W       >100                                           1X       0.1           1Y       >100                                                    0.8                                                                            1.0                                                                   1Z       1.0           1AA      0.6                                                     1.3                    2.2                                            1BB      30            1CC      15.7                                                    4                                                                              51                                                                    1DD      0.7           1EE      5.2                                                     0.7                    8.5                                            1FF      24            1GG      >100                                                    >100                                                                  1HH      1.3           1II      3                                                       1.2                    2.5                                                     5.6                    3.8                                            1JJ      9             1KK      1                                                       30                     3                                              1LL      <1            1MM      3                                                       >10                    1                                                       3                                                                     1NN      7             1OO      7                                                                              6                                              1PP      17            1QQ      5                                                       9                                                                     2        0.7           2A       2                                                       0.3                    5.5                                                     1.3                                                                            0.5                                                                            0.8                                                                            0.1                                                                            0.7                                                                            0.3                                                                            0.7                                                                   2B       4.5           2C       <1                                                      3.3                    0.6                                            2D       0.3           2E       0.1                                                     0.04                   0.5                                            2F       <1            3        1.9                                                     1                      9.4                                                     0.7                    40                                             3A       65            3B       40                                                      ≈100           >100                                           3C       23.3          3D       2.4                                                     28.8                   1.6                                            3E       7.7           4        10.3                                           4A       0.8           4B       6.9                                                     13                     21                                             4C       0.7           4D       ≈60                                             0.6                                                                            5.7                                                                            5.2                                                                   4E       >100          4F       >100                                           4G       >100          4H       0.04                                                                           0.8                                            4I       1.4           4J       33                                                      56                                                                             28                                                                    4K       51            4L       31                                                                             47                                             4M       11                                                                             >100                                                                           >200                                                                  ______________________________________                                     

We claim:
 1. A compound of the formula ##STR37## or a pharmaceutically acceptable addition salt thereof, wherein R^(a) is an aryl group substituted by 1-5 substitutents R^(4a) ;R^(1a) and R^(2a) together comprise a fused ring of the formula ##STR38## q is 0 or 1 R^(3a) is nitro; and wherein the R^(4a) substituents are independently selected from the group consisting of hydroxy, Y-substituted alkyl, alkylamino, dialkylamino, aryl amino, diarylamino, trialkylammonium, thio, --S(O)_(m) R⁷, --SO₃, carboxyl, alkoxycarbonyl, benzyloxycarbonyl, alkenyloxycarbonyl, carboxamido, N-phthalimido, cyanoalkoxycarbonyl, carboxyalkoxycarbonyl, benzyloxycarbonyl-alkoxycarbonyl, N,N-dialkylcarboxamido, trifluoromethyl and cyano; Y is selected from the group consisting of halogeno, trialkylammonium, amino, carboxy, pyridinium, triarylphosphonium, benzyloxycarbonyl, hexamethylenetetraminium, --N═CH--alkyl, --N═CH--aryl and --N═CH--N(alkyl)₂ ; R⁷ is C₁ -C₈ alkyl or aryl; and m is 0, 1 or
 2. 2. A compound of claim 1 having the structural formula

    ______________________________________                                          ##STR39##                                                                     wherein:                                                                       R.sup.1a, R.sup.2a                                                                     R.sup.a                                                                ______________________________________                                          ##STR40##                                                                              ##STR41##                                                              ##STR42##                                                                              ##STR43##                                                              ##STR44##                                                                              ##STR45##                                                              ##STR46##                                                                              ##STR47##                                                              ##STR48##                                                                              ##STR49##                                                              ##STR50##                                                                              ##STR51##                                                              ##STR52##                                                                              ##STR53##                                                              ##STR54##                                                                              ##STR55##                                                              ##STR56##                                                                              ##STR57##                                                              ##STR58##                                                                              ##STR59##                                                              ##STR60##                                                                              ##STR61##                                                              ##STR62##                                                                              ##STR63##                                                              ##STR64##                                                                              ##STR65##                                                              ##STR66##                                                                              ##STR67##                                                              ##STR68##                                                                              ##STR69##                                                              ##STR70##                                                                              ##STR71##                                                              ##STR72##                                                                              ##STR73##                                                              ##STR74##                                                                              ##STR75##                                                              ##STR76##                                                                              ##STR77##                                                              ##STR78##                                                                              ##STR79##                                                              ##STR80##                                                                              ##STR81##                                                              ##STR82##                                                                              ##STR83##                                                              ##STR84##                                                                              ##STR85##                                                              ##STR86##                                                                              ##STR87##                                                              ##STR88##                                                                              ##STR89##                                                              ##STR90##                                                                              ##STR91##                                                              ##STR92##                                                                              ##STR93##                                                              ##STR94##                                                                              ##STR95##                                                              ##STR96##                                                                              ##STR97##                                                              ##STR98##                                                                              ##STR99##                                                              ##STR100##                                                                             ##STR101##                                                             ##STR102##                                                                             ##STR103##                                                            ______________________________________                                    


3. A compound of claim 1 wherein R^(a) is phenyl or naphthyl, substituted by 1-5 groups R^(4a).
 4. A compound of claim 3 wherein R^(4a) is Y-substituted alkyl, alkylamino, dialkylamino or alkoxycarbonyl.
 5. A compound of claim 4 wherein Y is halogeno, benzyloxycarbonyl or triphenylphosphonium.
 6. A compound of claim 1 wherein q=0.
 7. A pharmaceutical composition comprising a PDGF inhibitory amount of a compound of claim 1 in a pharmaceutically acceptable carrier.
 8. A method of inhibiting the binding of platelet-derived growth factor by treating a mammal in need of such treatment with a inhibitory effective dose of a compound of the formula ##STR104## or a pharmaceutically acceptable addition salt thereof, wherein p is 0, 1, 2, 3, 4, 5, or 6 and R is hydrogen or an aryl group substituted by 1-5 substitutents R⁴, provided that R is not hydrogen when p=0;R¹ and R² taken together comprise a fused ring of the formula ##STR105## q is 0, 1, 2, 3 or 4; X and R³ are independently selected from the group consisting of hydrogen, halogeno, hydroxy, C₁ -C₈ alkyl, C₁ -C₈ alkenyl, C₁ -C₈ alkoxy, aryloxy, amino, alkylamino, dialkylamino, arylamino, diarylamino, trialkylammonium, thio, --S(O)₂ R⁶, --S(O)_(m) R⁷, --SO₃, nitro, --NHS(O)₂ alkyl, carboxyl, alkoxycarbonyl, carboxamido, N-alkylcarboxamido, N,N-dialkylcarboxamido, alkylcarbonylamino, arylcarbonylamino, alkylaminocarbonyloxy, alkoxycarbonyloxyl, alkylcarbonyloxy, trifluoromethyl, cyano, aryl, and substituted aryl, wherein the substitutents are 1-5 groups R⁴ ; and wherein the R⁴ substituents are independently selected from the group consisting of hydrogen, halogeno, C₁ -C₈ alkenyl, C₁ -C₈ alkynyl, hydroxy, C₁ -C₈ alkyl, Y-substituted alkyl, C₁ -C₈ alkoxy, aryloxy, amino, alkylamino, dialkylamino, arylamino, diarylamino, trialkylammonium, thio, --SO₂ R⁶, --S(O)_(m) R⁷, --SO₃, nitro, carboxy, alkoxycarbonyl, benzyloxycarbonyl, alkenyloxycarbonyl, carboxamido, N-phthalimido, cyanoalkoxycarbonyl, carboxyalkoxycarbonyl, benzyloxycarbonylalkoxycarbonyl, N-alkylcarboxamido, N,N-dialkylcarboxamido, trifluoromethyl, cyano and aryl; Y is selected from the group consisting of halogeno, trialkylammonium, amino, carboxy, pyridinium, triarylphosphonium, benzyloxycarbonyl, hexamethylenetetraminium, --N═CH--alkyl, --N═CH--aryl and --N═CH--N(alkyl)₂ ; R⁶ is amino, arylamino, alkylamino or dialkylamino; R⁷ is C₁ -C₈ alkyl or aryl; and m is 0, 1 or
 2. 9. A method claim 8 wherein the compound has the structural formula

    __________________________________________________________________________      ##STR106##                                                                    wherein:                                                                       R.sup.1, R.sup.2                                                                           R                                                                  __________________________________________________________________________      ##STR107##                                                                                 ##STR108##                                                         ##STR109##                                                                                 ##STR110##                                                         ##STR111##                                                                                 ##STR112##                                                         ##STR113##                                                                                 ##STR114##                                                         ##STR115##                                                                                 ##STR116##                                                         ##STR117##                                                                                 ##STR118##                                                         ##STR119##                                                                                 ##STR120##                                                         ##STR121##                                                                                 ##STR122##                                                         ##STR123##                                                                                 ##STR124##                                                         ##STR125##                                                                                 ##STR126##                                                         ##STR127##                                                                                 ##STR128##                                                         ##STR129##                                                                                 ##STR130##                                                         ##STR131##                                                                                 ##STR132##                                                         ##STR133##                                                                                 ##STR134##                                                         ##STR135##                                                                                 ##STR136##                                                         ##STR137##                                                                                 ##STR138##                                                         ##STR139##                                                                                 ##STR140##                                                         ##STR141##                                                                                 ##STR142##                                                         ##STR143##                                                                                 ##STR144##                                                         ##STR145##                                                                                 ##STR146##                                                         ##STR147##                                                                                 ##STR148##                                                         ##STR149##                                                                                 ##STR150##                                                         ##STR151##                                                                                 ##STR152##                                                         ##STR153##                                                                                 ##STR154##                                                         ##STR155##                                                                                 ##STR156##                                                         ##STR157##                                                                                 ##STR158##                                                         ##STR159##                                                                                 ##STR160##                                                         ##STR161##                                                                                 ##STR162##                                                         ##STR163##                                                                                 ##STR164##                                                         ##STR165##                                                                                 ##STR166##                                                         ##STR167##                                                                                 ##STR168##                                                         ##STR169##                                                                                 ##STR170##                                                         ##STR171##                                                                                 ##STR172##                                                         ##STR173##                                                                                 ##STR174##                                                         ##STR175##                                                                                 ##STR176##                                                         ##STR177##                                                                                 ##STR178##                                                         ##STR179##                                                                                 ##STR180##                                                         ##STR181##                                                                                 ##STR182##                                                         ##STR183##                                                                                 ##STR184##                                                         ##STR185##                                                                                 ##STR186##                                                         ##STR187##                                                                                 ##STR188##                                                         ##STR189##                                                                                 ##STR190##                                                         ##STR191##                                                                                 ##STR192##                                                         ##STR193##                                                                                 ##STR194##                                                         ##STR195##                                                                                 ##STR196##                                                         ##STR197##                                                                                 ##STR198##                                                         ##STR199##                                                                                 ##STR200##                                                         ##STR201##                                                                                 ##STR202##                                                         ##STR203##                                                                                 ##STR204##                                                         ##STR205##                                                                                 ##STR206##                                                         ##STR207##                                                                                 ##STR208##                                                         ##STR209##                                                                                 ##STR210##                                                         ##STR211##                                                                                 ##STR212##                                                         ##STR213##                                                                                 ##STR214##                                                        __________________________________________________________________________


10. A method of treating atherosclerosis, cancer, retinal detachment, pulmonary fibrosis, arthritis, psoriasis, glomerulonephritis, and restenosis following angioplasty or vascular surgery, in a mammal in need of such treatment, comprising administering an effect amount of a composition of claim
 7. 11. A method of inhibiting PDGF comprising administering an effective amount of a composition of claim 7 to a mammal in need of such treatment.
 12. A method of claim 8 wherein the compound has the structural formula ##STR215## wherein ##STR216## is selected from the group consisting of --CH₂ --C₆ H₅,--(CH₂)₂ --C₆ H₅, --(CH₂)₃ --C₆ H₅, --CH₃, --C₄ H₉, --C₁₂ H₁₅, 3-chloropropan-1-yl or ##STR217## 